Heat exchanger for gas turbines



Aug. 25, 1964 s. B WILLIAMS ETAL 3,145,534

HEAT EXCHANGER FOR GAS TURBINES Original Filed Jan. 20, 1960 3Sheets-Sheet l ug 25, 1954 s. B. WILLIAMS ETAL 3,145,534

HEAT EXCHANGER FOR GAS TURBINES Original Filed Jan. 20, 1960 3Sheets-Sheet 2 Aug- 25, 1964 s. B WILLIAMS ETAL 3,145,534

HEAT EXCHANGER FOR GAS TURBINES Original Filed Jan. 20, 1960 3Sheets-Sheet 3 United States Patent O 3,145,534 HEAT EXCHANGER EUR GASTURIEINES Sam B. Wiiliams and John F. iones, Birmingham, Mich.,

assigner-s to Williams Research Corporation, Birmingham, Mich., acorporation of Michigan Original appiication Ilan. 20, 1960, Ser. No.3,691. Divided and this appiicaticn Im. 6, 1961, Ser. No.

1 Claim. (Cl. 611-3951) This -application is a division of ourapplication Serial No. 3,691 filed January 20, 1960.

This invention relates to gas turbines, and more particularly to heatexchangers of the rotary type for transferring heat in such turbinesfrom the exhaust gases to the intake air.

It is an object of the invention to provide a novel and improved heatexchanger apparatus which permits a substantially greater ow areathrough the heat exchanger matrix for a given gas turbine housingdiameter, and in which ecient ow paths for the intake and exhaust gasesare maintained.

It is another object to provide an improved heat exchanger constructionof this nature which permits greater iexibility in the overall layout ofthe gas turbine and in which the heat exchanger ow areas may besubstantially increased without increasing the turbine diameter.

It is another object to provide a novel and improved heat exchangerconstruction of this character which includes improved sealing means forpreventing gas flow between the adjacent heat exchanger sections.

Other objects, features and advant-ages of the present invention willbecome apparent from the subsequent description, taken in conjunctionwith the accompanying drawings.

FIGURE l is a side elevational view of a gas turbine partially incross-section along the line 1-1 of FIGURE 2 and incorporating the novelheat exchanger construction of this invention;

FIGURE 2 is a cross-sectional view in elevation taken along the line 2-2of FIGURE 1 and showing the arrangement of the intake and exhaust ducts;

FIGURE 3 is a top elevational View ot' the gas turbine housing taken inthe direction of the arrow 3 of FIG- URE 2 and showing the air collectorscrolls and exhaust ports;

FIGURE 4 is a cross-sectional View taken along the line 4-4 of FIGURE 1and showing the heat exchanger ring gear and driving pinions;

FIGURE 5 is a perspective view of one of the seals for the high pressureintake chambers;

FIGURE 6 is a cross-sectional View taken along the line 6 6 of FIGURE 5and showing the seal construction; and

FIGURE 7 is a cross-sectional view similar to FIG- URE 6 showing amodied form of this seal.

In general terms, the invention comprises a heat exchanger orregenerator of the cylindrical matrix type, the heat exchanger being ofelongated annular cylindrical shape. The regenerator matrix surroundsthe combustion chamber and turbine blades and extends axially asubstantially greater distance than the matrix thickness between itsinner and outer diameters. Intake chambers leading from the compressordiffuser and exhaust collection chambers are alternately arranged aroundthe outer periphery of the matrix, while the inside of the matrix isconnected to alternate intake and exhaust charnbers leading to thecombustion chamber and from the turbine respectively. Bellows type sealsin the form of arcuately shaped closed loops serve to seal the highpressure chambers with respect to the matrix, these seals 3,145,534Patented Aug. 25, 1964 being engageable with the inner and outer matrixsurfaces. Annular low pressure seals are engageable with the endsurfaces of the matrix and serve to seal the exhaust chambers. Thematrix vis supported for rotation by a plurality of driving pinionsengageable with an ice ` internal ring gear as well as by the seals.

Referring more particularly to the drawings, a gas turbine assemblyincorporating the principles `of the invention is generally indicated at11 and comprises an air inlet 12 which leads to a compressor 13V and adifuser 14. Compressor 13 is of a radial type and is driven by a shaft15 which extends through an annular combustion chamber 16 and isconnected to a first stage turbine 17. A second stage turbine 18 isconnected to a shaft 19 which extends toward the other end of turbineassembly 11. Shaft 19 drives a power output pinion 21, and an accessoryshaft 22 is disposed Wi-thin shaft 19 and is connected to first stageturbine 17, shaft 22 driving a pinion 23. This pinion serves to drivethe heat exchanger matrix through a gear train which includes a gear 24meshing with pinion 23 and on a cornmon shaft with a pinion 25 behindshaft 22 in FIGURE l. Pinion 25 drives a pair of gears 26 havingco-axial pinions 27 connected thereto, these pinions driving a pair ofgears 28. Gears 28 are secured to shafts 29 rotatably mounted in ahousing portion 31 of turbine 11, and the opposite ends of shafts 29carry pinions 32 which mesh with an internal ring gear 33 on the heatexchanger matrix which is generally indicated at 34.

Matrix 34 is of elongated annular cylindrical shape and comprises a coresection 35 having alternate passages 36 between the inner and outermatrix surfaces. As seen in FIGURE 1, the length of matrix 34 issubstantially greater than the thickness between its inner and outersurfaces, and the matrix surrounds combustion chamber 16 as well as rstand second stage turbines 17 and 18 and the outlet from the second stageturbine. It should be noted that the length of heat exchanger 34 couldbe varied within the principles of the invention in accordance with thedesired flow areas, this variation being possible of course Withoutincreasing the diameter of the matrix.

A ring 37 is provided at one end of matrix 35, internal gear 33 havingan annular tlange 38 which is secured to the other end of the matrix. Apair of annular seals 39 and 41 are engageable with ring 37 and flange38 respectively, these seals comprising expandable annular metal membersin rubbing engagement with parts 37 and 38. Seal 39 is secured to adisc-like plate 42 which in turn is carried by a housing portion 43,while seal 41 is carried by an annular member 44 of channel shapedcross-section which is secured to a mounting ring 45. Bolts 46 extendbetween ring member 42 and housing portion 31, these bolts beingsurrounded by compression tubes 47 yand serving -to hold together thehousing components.

The outer periphery of heat exchanger 34 is connected with a pair ofhigh pressure intake chambers 48 and a pair of exhaust collectorchambers 49, these chambers being in circumferentially spaced relationas seen in FIGURE 2. Intake chambers 48 are formed by domeshaped housingmembers 51 which are connected to air collector scrolls 52 as seen inFIGURE 3, these scrolls leading from diifuser 14. Exhaust collectorchambers 49 are formed by housing portions 53 which are likewise ofdome-like shape and lead to a pair of exhaust ports 54 also seen inFIGURE 3, these ports leading toward the opposite end of the turbineassembly. It will thus be seen that intake air under high pressure willflow inwardly from chambers 48 through matrix 34 as indicated by thearrows in FIGURE 2 and the combustion aliases gases will iiow outwardlyfrom the matrix into exhaust collector chambers 49. Housing members 5land 53 are secured to ring member 42 and annular member 45 by bolts 55,and their adjacent edges have mating ilanges 56 and 57 respectivelywhich vare closely adjacent the outer surface of matrix 34.

The inner surface of matrix 34 connects with a pair of high pressureheated air chambers 5S which are radially aligned with chambers 48 and apair of hot exhaust plenum chambers 59, opposite chambers 49. ChambersS3 are formed by a pair of annular shields 6l and e2, which lead to theforward and rear portions of the combustion chamber respectively, asseen in FIGURE l, and by a pair of axially extending shields 63 whichextend between shields 6l and 62 and also between the upper and lowerchambers 5S, as seen in FGURB 2. Shields 6l, 62 and 63 together form acontinuous chamber which surrounds the major portion of combustionchamber iti and connects with both chambers 55S, so that the heated airilowing inwardly from the matrix may iiow through the combustion chamberlouvers4 As shown in FIGURE l, these openings comprise an annular inneropening 64 at thc rear of the combustion chamber, louvers 65 at theforward portion of the combustion chamber, and passages 66 which lead tothe space adjacent louvers 65 and also directly into the combustionchamber adjacent the outlet thereof for secondary combustion airpurposes. Exhaust plenum chambers 59 are formed by shields e3 which.have curved portions d'7 seen in FIGURE 1 which connect with the outletof second stage turbines i8, an annular shield 63 leading from theturbine outlet in spaced relation with shield portions 67, and anannular member 69 connecting t e outer portion of shield 68 with theinner edge of annular member 45' and substantially aligned with the mainportions of shields 63, as seen in FGURE 1. it will be noted that thepassages formed by shields 67 and 63 will be curved in the direction ofgas flow.

The sealing means for the various chambers connected to exchanger 34comprises seals 39 and 41 as well as a pair of seals generally indicatedat 71 for chambers 48 and a pair of seals generally indicated at 72 forchambers 5S. As indicated previously, seals 39 and 41 are of a lowpressure type and serve to seal chambers 59 from chambers 49, theexhaust gases in these two chambers being at low pressures relative tothe pressures in charnbers 4S and 53. Seals 39 and 4l also serve tosupport matrix 34 in an axial direction as seen in FGURE l. Seals 71 and'72 are similar to each other in construction, one such seal being shownin detail in FIGURES 5 and 6. The seal is of bellows construction andcomprises a pair of shoes '73 and 74 each of which forms a closed loopof generally rectangular shape which is arcuately curved to conform tothe corresponding duct opening. Shoes 73 and 7d are disposed on oppositesides of a tiexible bellows 75 formed of strips of elastic materialwhich forms an annular pressure chamber '76. The shoes are preferablyfabricated of relatively thin material so that they may ex duringassembly and will conform to any irregularities in the adjacent surfacesof matrix 34 as the latter rotates. Bellows portion 7S is so constructedas to be expandable in a direction so as to separate shoes 73 and 74 asseen in FIGURE 6. The seal may be constructed by first bending thecomponents to the proper arcuate shape and then brazing or otherwisefastening them together, after which the assembly will still be capableof slight bending as necessary during installation. For this purpose,the inside shoe 74 may be constructed of a slightly smaller size thanshoe 73 so that after the parts are bent to their arcuate shape thesizes will match, A pressurizing air connection '77 is preferablyprovided at one corner of the seal so that chamber '75 may be kept atproper pressure, this connection leading from any appropriate portion ofthe turbine assembly such as the diffuser.

As seen in FIGURES l and 2, seals 7l are disposed adjacent anges 5'6 ofhousing portions Sl, engaging these flanges as well as the adjacentportions of the outer surface of matrix 34. Seals 71 may be fastened inplace or may be held in position by-friction and pressure duringoperation. Seals 72 are preferably secured to supporting members 78which are of rigid construction, conform to the openings of' chambers6l, and are secured to housing members 3l and FIGURE 7 shows a modifiedform of bellows seal construction which may be used in appropriatecircumstances, particularly where larger clearances between the matrixand adjacent parts are desired. This seal is generally indicated at 7and comprises a plurality of corrugated elastic strips Si joinedalternately at their inner and outer edges and forming a single closedchamber d2.. The outermost strips are secured to shoes S3 and 84 in themanner described above with respect to seals 7 and 72. It will be notedthat by providing four elastic strips on eachV side of the seal, as seenin FIGURE 7, the available expansive movement of the bellows will besubstantially greater than if only two strips are used as seen in FIGURE6.

The operation of the novel heat exchanger construction will be evidentfrom the foregoing description. Compressed air delivered from compressor18 through air collector scrolls 52 will enter chambers 48 and will passinwardly through the heat exchanger which is being rotated by meshing ofpinions 32 with gear 33. This air will be heated as it passes throughthe matrix and will enter chambers 58 from where it will flow at highpressure into combustion chamber i6. After the burning gases have leftsecond stage turbine i8 they will pass through chambers 59 and outwardlythrough the matrix into chambers 49, heating the matrix as they ilowthrough its passages. It will be observed that the total ow area for thegases ilowing inwardly or outwardly will be determined by the axialextent of the heat exchanger as well as the circumferential distanceallotted to each chamber. Because of the difference in pressures, thecircumferential distance may be somewhat greater for the exhaustchambers than for the high pressure intake chambers. In any event, sincethe heat exchanger may extend the entire axial distance between the rearof the combustion chamber and the second stage turbine outlet, theavailable ow areas will be substantial for a given total outsidediameter of the housing. At the same time, the sealing means for thevarious chambers are eciently and compactly arranged without complicatedsealing structures being required. The matrix will be supported bypinions 32 and seals 39 and 41 so that it may rotate without unduerestriction while maintaining its proper position with respect to theseals.

While it will be apparent that the preferred embodiments of theinvention disclosed are well calculated t0 fulll the objects abovestated, it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the properscope of fair meaning ofthe subjoined claim.

What is claimed is:

In a gas turbine, a compressor, an annular combustion chamber co-axialwith and spaced axially from said compressor, a turbine wheel spacedaxially from and connected to the outlet of said combustion chamberremote from said compressor, a heat exchanger matrix of annularcylindrical shape surrounding said combustion chamber and turbine wheel,the axial length of said matrix being substantially greater than thethickness thereof between its inner and outer surfaces and alsosubstantially greater than the axial length of the combustion chamberwhich it surrounds, a substantial portion of said matrix being disposedbetween two imaginary parallel planes extending at right angles to theturbine axis and just containing said combustion chamber, high pressureinlet chambers formed outwardly of said matrix and facing the outersurface thereof, means connecting said compressor to said chambers, apair of heated air chambers formed radially inwardly of said highpressure chambers and facing the inner matrix surface, annular shieldmeans connecting said heated air chambers to said combustion chamber andforming a continuous annular space exposed to the combustion chamber, apair of exhaust plenum chambers circumferentially spaced from saidheated air chambers and facing the inner matrix surface, duct meansconnecting the outlet of said turbine wheel to said plenum chambers, anda pair of exhaust collector chambers formed outwardly of the matrix andaligned with said 10 plenum chambers.

References Cited in the le of this patent UNITED STATES PATENTS2,969,644 Williams Jan. 31, 1961 3,032,989 Oprecht May 28, 1962(Corresponding to French Patent 1,205,792)

FOREIGN PATENTS 1,185,339 France Feb. 16, 1959 1,205,792 France Aug. 17,1959 620,602 Great Britain Mar. 28, 1949

